"Celluloid! Film stock!... What... what kind of film stock?"

"Well, as it happens, I can tell you, chum. Probably because there is so much copying of documents to do down here, with all these secret stations all over the shop, we do happen to have made a qualitative study of film celluloids, photo-copying materials and similar stuff — in particular those used for micro film rolls, which are quite different from the others. They have to be far more flexible, you see, and the emulsion must —"

"And the traces... ?" Mark interrupted, excitement quickening his voice.

"Are of that kind. They're from a micro-roll."

"Let me get this straight: there are microscopic traces of this celluloid mixed in with the white powder?"

"Right. That's what I meant by a negative reply… negative, see!"

"What kind of traces? If you can say, that is."

"Well, they're more scrapings than anything else, really. But they are very small."

"Would they be consistent...No, let me put it this way. The powder was found in a small cylindrical recess in this Porphyry lighthouse. Are your celluloid scrapings consistent with a roll of microfilm having been inserted... pushed perhaps... into that cavity?"

"How wide is the cavity?"

"Half to three-quarters of a centimetre, roughly, I should say."

"Then they would, then. Yes. Porphyry's a rough stone with very large crystals. A recess for secreting microfilm wouldn't be polished like the outside, and the usual size roll would certainly get a trifle scraped along the edge when it was shoved in there."

"Thus the scrapings, thus the minute traces of celluloid?"

"Thus the scrapings."

"Thank you," Mark said. "Thank you very much indeed."

He walked slowly back into the bar — darkened now until the official opening time at half past five — and sat down.

He was conscious that both he and April had been deliberately reserving judgment on one crucial aspect of the mystery: if illicit drugs were being supplied to those in the know through the medium of the lighthouses with the secret compartments, then had the late Sheila Duncan been in on the deal, or had she been an unknowing accomplice?

Now, however, now that it had been conclusively established that there was no drug involved, a different question arose. For if it was proved — as it seemed to be — that the Porphyry lighthouses had been used simply as a means of secretly transporting microfilm, then it must also be asked: first, what could the microfilms depict; secondly, who could have taken them? And to each question, in view of the people known to be involved, there seemed to Slate to be only one answer...

It would be too much of a coincidence to expect the films to be of anything else but the DEWS station and other secret NATO installations on Trewinnock Tor and the surrounding moors; and who was there more likely to have taken them than Sir Gerald Wright — the rich man whose house overlooked the Tor, the popular local squire who was so frequent a guest in all the military messes of the area? Moreover, if it was Wright who was the secret spy passing out filmed information, then what arose at once was: who was receiving this information? And in view of the data passed on to April Dancer by Waverly, there could again only be one answer to this — the Council of THRUSH, who would be eager to exploit the information both for their own underground purposes and to sow discord among the great powers.

Mark rose to his feet and strode to the window. It was getting dark and the ebbing tide was lowering the masts and rigging in the harbour, though the wind still howled above his head in the chimneys of the old inn. He passed one hand agitatedly through his short, fair hair. He was very worried.

For if the squire was indeed working thus for THRUSH, and if his late girlfriend had been in charge of the booth from which the lighthouses containing the film had been collected, then it scarcely seemed likely that she had been unaware of what was going on. Had it been only drugs, and had they been unconnected with Wright, then it might just have been possible that Sheila was in ignorance of the deal. But since it was a matter of espionage — and directly connected with her boyfriend at that — then there seemed little doubt at all.

But if Sheila Duncan had known that Wright was passing microfilmed information about the NATO installations to THRUSH, and more particularly if she had herself connived at this, then the possibility — the near certainty — arose that she had in fact been a double agent.

And if the dead girl had been a double agent, then was it not likely that the squire, her boyfriend, had been aware of everything she herself knew about U.N.C.L.E.?

In which case, the squire might very well know — in detail — all about April and Mark... the squire into whose head quarters April Dancer had just voluntarily delivered herself...

Slate snapped a match he had picked up from an ashtray viciously in two and strode from the room. In the yard behind the pub, he hurled himself into the driving seat of the Matra-Bonnet, gunned the motor furiously for a few moments, and then rocketed out on to the quay and headed for the square and the road leading up to the Tor.

If the girl from U.N.C.L.E. had delivered herself into the hands of the enemy, then it was up to him to get her out!

CHAPTER TWELVE: APRIL'S BAG OF TRICKS

"IT'S frightfully nice of you to bother to come and see me, Miss Dancer," Sir Gerald Wright had said abruptly, swinging round from the cocktail cabinet in his elegant drawing room and staring April in the eye, "though I do rather regret the stratagem — the duplicity, I might almost say — which led you to pretend you had missed your way on my property."

"I'm afraid I don't quite…"

"Oh, come, Miss Dancer! I had expected better of the stalwarts of U.N.C.L.E."

"The stalwarts of what?" She had stared at him in a dismay she could barely conceal.

"My dear young woman, pray do not trifle with me. You are a general assignment agent from the New York head quarters of the United Network Command for Law and Enforcement. You are a graduate of a New England college and a descendant of David Harum. You are here, I imagine, on account of that troublesome young woman at the circus who turned out to be a part-time agent for your organisation — and your colleague from Section Two on this assignment is a 31-year-old transfer from London Headquarters named Mark Slate. Do I make myself clear?"

The girl had swallowed a mouthful of her sherry and set the glass carefully down on a Sheraton occasional table. "So," she had said with a coolness she was far from feeling, "the cards are on the table, are they? Then you, one assumes, must be from the organisation called THRUSH?"

His tanned face had creased briefly into a smile totally with out humour. "I have that honour — not the Council... yet... but I am in charge of the particular Satrap which has been milking the secrets of Trewinnock Tor. A task which will be completed tonight, as it happens."

"Then you won't mind telling me all about it?"

"On the contrary, Miss Dancer. We of THRUSH are trained to take things for granted. The assignment is due to terminate tonight; you are most unlikely to leave this house alive — yet mistakes do happen, have happened. It profits me nothing to tell you how clever we are; I know how clever we are. In the books, the spy about to be liquidated is told all and then escapes to worst his adversaries. In real life the spy does not escape — and to tell him anything at all is a sheer waste of time."